Have you looked at his throat? You can do it without depressing his tongue. Use a flash light and play a game. Some sounds result in tongue pushing out of the way. It seems like just having him push his tongue out might work. If he's eating as usual and not complaining and it's a sore throat, it's a mild one that does not need treatment. The only sore throat that gets treatment is a strep infection and that is very painful. He would be complaining.
I've also known of kids and adults running a temperature without having anything wrong. I'd ask the advice nurse before I took him in. If it is a virus as you suggested as a possibility, remember that there is nothing that you can do for a virus.
Since he is in no distress and it's been such a short time, I suggest that it's unlikely that the doctor will be able to diagnose or even do anything for him. After years of experience I go to the doctor less and less realizing at last that they can't know everything and most things "run their course" and are gone.
If his fever is not causing him discomfort, I would not give him Tylenol. Fever serves the desirable function of killing whatever is causing the fever.
Also, babies and children tend to run higher fevers than adults. A fever of 101.8 is not serious.
Talk with the advice nurse.